Phase II evaluation of intrathecal thiotepa is being carried out in patients with meningeal leukemia and meningeal carcinomatosis. Thiotepa represents the third intrathecal chemotherapeutic agent available for the treatment of meningeal disease, and approximately one-half of the patients showed a complete response with reduction in cerebral spinal fluid blast count. It is anticipated that additional patients will be accrued and this study completed during the course of the next year.